nersut
Veteran Member
Joined: September 2012
Posts: 223
|
Post by nersut on Oct 17, 2012 21:12:58 GMT -5
Tillykke med dagen Anders  Very interesting build, looking forward to see the test video  Cheers Erik |
|
|
|
Post by Johansson on Oct 18, 2012 0:33:21 GMT -5
Tack ska du ha! It will probably take a while before I have everything set for a test, I need to find a suitable location and figure out a date that works for the ones helping out with the test run. Rigging up some sort of thrust measurement might take some time as well. Hopefully the gas turbine gearbox arrives so I can continue working on that project in the meantime. |
|
|
|
Post by Johansson on Oct 29, 2012 18:01:43 GMT -5
Today I had a 15L scuba tank filled with 5 litres of NOX and got some work done on the test stand, first off I secured the engine firmly to the test stand with four M12 bolts.  Then I rigged up an old spark transformator with a lenght of speaker wire to see if it would produce a good spark without burning through the wire insulation, it worked fine so I will use it to ignite the NOX/methanol mixture. Once the engine starts the wire will be spat out through the nozzle instantly.  All gauges were collected around the pressure regulator so I can use a video camera to log all the values during the run, very useful when we try to figure out why the engine blew up.  A 200kg load cell was fitted to the test stand at the same height as the centre of the thrust chamber, a friend will write a program so the thrust can be logged on a time axis in my laptop.  And finally the test stand in all its glory!  Cheers! /Anders |
|
8maddog8
Member
Joined: July 2012
Posts: 24
|
Post by 8maddog8 on Oct 29, 2012 20:40:54 GMT -5
Nice work! Cant wait to see this thing running and see how much thrust it makes  |
|
|
|
Post by Johansson on Oct 30, 2012 1:12:59 GMT -5
Thanks! I will set the propellant tank pressure as low as possible (still has to be higher than the NOX vapour pressure) for the first test, at this point I want to see if the engine ignites properly and if the coolant system carries away enough heat for the thrust chamber to survive a low thrust run. If it seems to work I can increase the propellant pressure for the next test and aim for a decent thrust reading, but wise from experience I assume that I will have to modify it a couple of times before it runs ok. Cheers! /Anders |
|
|
|
Post by ernie wrenn on Oct 30, 2012 8:37:08 GMT -5
Do you have a EMERGENCY pull start rope. This is nice, can't wait for the thrust figures..
ernie
|
|
mator
Junior Member
Joined: January 2012
Posts: 76
|
Post by mator on Oct 30, 2012 12:09:15 GMT -5
Havent seen you here for quite long time)))
Are you sure that yours trolley (cart) on which your engine is mounted will move as you want? As I see from foto, all yours construction, on which acts a force of thrust, is balanced with strain gauge transducer that is very small versus all construction. In my opinion, if thrust will be some times higher than weight of all construction, this construction can be unstable. Maybe it is needed some rails to limit the number of degrees of freedom of construction?...
|
|
mator
Junior Member
Joined: January 2012
Posts: 76
|
Post by mator on Oct 30, 2012 12:15:00 GMT -5
As I understand you had a birthday recently? Happy birthday!
Tillykke med dagen Anders!!! (I hope that it is that thing that iam think about))))
|
|
wolfdragon
Senior Member
Joined: April 2011
Posts: 287
|
Post by wolfdragon on Oct 30, 2012 13:40:35 GMT -5
you may want to further stiffen up the mounting point for that strain gauge, defection in the bar as well as the sled will hinder an accurate thrust measurment
|
|
|
|
Post by Johansson on Oct 30, 2012 15:16:32 GMT -5
Mator: Thanks! The cart will be running on rails so it can only go towards the load cell.
Wolfdragon: Good idea, I will use all destructive force available in my 70 kg body to try to bend the handlebar. If needed I will add some strenghtening rods to it.
|
|
mator
Junior Member
Joined: January 2012
Posts: 76
|
Post by mator on Oct 31, 2012 8:26:58 GMT -5
Ok. Can you tell me something about your strain gauge transducer? I now have signet in rocket - model club in my univercity. There are some interesting progects as solid rocket mounted on plane that mounted on helium balloon. And peroxide H2O2 engine.
|
|
|
|
Post by Johansson on Oct 31, 2012 17:45:24 GMT -5
I know practically nothing about the load cell, I rely completely on my friends to get it working. =) As I said before I got 5 kg of NOX filled in one of my 15L scuba tanks, without a burst disc I wanted to make sure there was plenty of room left for the liquid to expand so I didn´t want to fill it more than that.  I bought a 35kg digital luggage scale today that I will use to measure how much NOX I am filling over to the race tank, it cost only a few pennies and is very compact.  I hooked the NOX bottle up with the gauge and hung it from the ceiling to see if everything would look ok, I have had a short hydraulic hose made just for this purpose so there won´t be overly much liquid NOX in the fill hose that goes to waste.  Hopefully my friend will have the thrust logger fixed in a week or so, not much left to do then before it is ready for a run! Cheers! /Anders |
|
|
|
Post by racket on Oct 31, 2012 19:34:36 GMT -5
Hi Anders
LOL, now thats a foolproof decanting method , "KISS" at its best :-)
Cheers
John
|
|
|
|
Post by Johansson on Nov 5, 2012 13:47:47 GMT -5
Here is this years Speed Weekend poster, my friends in Svarthålet Racing made it to the front page!  |
|
|
|
Post by racket on Nov 5, 2012 14:19:10 GMT -5
Hi Anders
Now that should get peoples attention .....................is the 1/2scale Argus back together after its "side splitting" time last year ??
Cheers
John
|
|
